Telephone system.



'E. R. CORWIN. TELBPHONHSYSTEM. APPLICATION FILED 001212, 1908. RENEWED JULY 18, 1911,

. m W/fnesses.

M fi Z M Patented Aug: 26, 1913.

- UNITED STATES PATENT orFIoE.

' rAcr'URING COMPANY, or CHICAGO, r'LLINoI's;

Specification of Letters Patent.

Patented Aug. 26,1913.

Application filed October 12, 1908, Serial No. 457,197. Benewed July 18, 1911. Serial 110.; 639,203.

- To all whom itmag concern:

Be it known that I, ELMER R. Conwin, citizen of the United States, residing at Chlcago, in the countyof Cook and State of Illinois, have'invented a certain new and useful Improvement in Telephone Systems, of which the following is a full, clear, con-v else, and exact descriptlon, reference being had to the accompanying drawings, forming.

a part of this specification.

My invention relates to telephone exchange systems, some features thereof being of particular service in connection withfmultipleswitch-board systems to which, 'however, the invention is not to be restricted.

The invention in its various aspects, 1s

. well exhibited by the accompanying drawing, showing one of'the embodiments of the invention as applied to a multiple switchboard system, there being illustrated'two telephone sub-stations A B at each of which there is shown a telephone switch hook a adapted to support'a receiver 2) which serves to include said switch-hook in circuit with a signal hell 0," and a condenser c, that are ineluded by the switch-hook in a bridge of the mitter f associate telephone line. When the receiver is free of the switch-hook, said switch-hook opens the bridge containing the signal bell 0 and condenser c and includes the receiver 6 and transmitter f in. circuit and places the retardation coil f in'parallel with a receiver b for the purpose ofsupplying the trans-' with current from the common batterycf The-limbs'g and h of each telephone line are shown in this instance as terminating in the armature switches of the of "the uppermost armature switch constituting the terminal of a conductor that contains a line relay 2' and the common battery 4 while the normal contact of the lowermost armature switch of the relay 2' is grounded.

lVhe'n a call is sent to the exchange by the- -calling subscriber in removing his switchhook,-the magnet 41 is included in the circuit that includes thebattery i and the limbs g and h of the telephone line, as will be apparent by an inspection of the drawing.

' lamp,

Upon the closure of the circuit through the magnet .6 a circuit is established through the line signal-display device i preferably in the form of a small incandescent which circuit includes the battery i? and front contact of the magnet The front or alternate contacts of the armature sw tches of the cut-off relay 6 constitute the normally separated terminals of sections of the line limbs g and it that extend to the multiple jacks is. When an operator answers a call by inserting the answering plug Z Within an answering jack, a circuit is established through the cut-off relay 2' which may be traced from the grounded terminal of said cut-01f relay, through the winding of the relay, the thimble of the jack is engaged by the plug Z, the sleeve of the jack, the relay m, the battery F, to the grounded terminal of said battery. The cut-offrelay 2' and the relay m are thus included in a local circuit that serves to energize said cut-oft relay and maintain the spring-jack extensions ofthe telephone line in connection with the arms.- ture switches of said cut-off relay until the circuit of said cut-off relay is broken by the.

,withdrawal of the plug Z from the associate spring jack. The system illustrated being a two-wire metallic circuit system, one of the talking strands of the --cord circuit (inthis instance the talking sleeve strand of the cord circuit). is employed to take part in establishing the local circuit for the cut-off relay. i, with the .results that have been stated. When the cut-olfrelay has been energized the line relay 2' is excluded from circuit, and, being ,denergized, excludes the line signal-display device 71 from circuit. The receiver b at the calling station being off of its of the cord circuit which includes the relay m, the battery f and another relay n, is closed, so that the relay n is energized at the ELMEIR, R. CORWIN, OF CHICAGO, ILLINOIS, ASSIGNOR TO CORWIN TELEPHONE MANU- I hook, the bridge between the talking strands same time with relay m, whereby circuit through the calling subscribers supervisory or clearing-out signaln is opened at relay n.

WVhen the calling subscriber is through, he restores his receiver, thereby opening the circuit of the relay n, the signal device a then being included in. circuit owing to the continued energization of the relay m,

wvhereby the operator will know that the calling subscriber has restored his receiver.

Then the operator removes the answering plug, "the signal device n is restored to nor lnal owing to the breakage of the local circuit-including the relay m. After the operatorhas plugged into the answering jack of .a calling subscriber, a circuit is established which may be traced from the grounded relay 0 to the normal contact of the lowermost armature switch of relay p, said armature switch, to the right-hand armature the connecting plug r to the test thimble of a 'line jack of the desired subscribers line, audit the line is busy, a test circuit is established which may be traced from the grounds,

ed battery f to the sleeve of some plug engaging some jack oithe desired subscribers line, thence to the thimble tested, the tip of thetesting plug, the back contact of the uppermostarmature switch of the relay [2, through one-half of the winding of the op erators receiver to the grounded buzzer 9 whose armature serves by its vibration to open and close the circuit of said buzzer 9 said buzzer being in serial relation with a receiver winding of the operators receiver r winding of the relay .p,

and the balance of the instrumentalities:

that are included in'the test circuit. If the line desired is idle, there will be no battery f upon any of the thimbles of its jacks, in which event the relay g willnot be included in any operating circuit, so that the operator will know that. the line desired is idle and maybe called. The operator inserts the connecting plug rin a line. jack of a desired line that *may be. called, whereupon a number of changes in'the operated conditions of the plug circuit apparatus occur, which I will now describe.

, The relay 'p is included by the connecting plug in a local circuit which may be traced from the grounded battery p -through the sleeve strand of the connecting plug 1', the

i thimble of an engaged jack, to the cut-off relay z'fof' the. called subscribers line, said cutoff relay preventingthe called subscriber from operating his line signal when he .responds. The armature switches of the relay p are thereupon attracted, the lowermost armature switch serving to open the circuit including the relayo, whereby the operators telephone outfit is excluded from connection with the plug circuit and the talking battery f is removed from connection with the operators transmitter. Ringing current is then applied to the called subscribers line, but before describing the manner in which the ringing or signaling current is thus applied, I will describe the supervisory apparatus that is controlled by the called subscriber.

- Thesupervisory apparatus includes a relay s contained in a grounded tap from the a portion of thesaid supervlsory relay 8, including, when the called subscriber has responded, a portion of the tip strand of the plug circuit, the tip side of the called subscribers line, the'sleeve side of the called subscribers line, a por-' tion of the sleeve strand, and the battery p When the supervisory relay circuit 8 is closed, the supervisory display device SP -is excluded from circuit, but until the called subscriber responds, the supervisory relay circuit 8 is not open, whereby the operator,

'by observing the signals is aware that the called subscriber has not responded, said signal device 8 being included in a circuit which may be traced from the grounded terminal of the lamp 8 to the left-hand armature switch of the relay 8, to the battery P- 'been energized upon the insertion. of the connecting plug within the line jack of a called subscriber, places the normally isolated sections t t of the talking strands of the plug circuit in connection with the uppermost armature switches of the relay 1), whereby said talking strand'sections are connected with the called line. These talking strand sections are normally connected with the terminals of a source of signaling current u by the upper armature switches of the relay '0 when in their normal unattracte'd position,zwhereby said source of signaling current u is included in circuit with a called subscribers line.

In order that the'signaling current may beintermittently applied to the called line, brushes-u are employed which bear upon collars a that are made of alternating strips of conducting and non-conducting material. Duringthe time that currentis' being impressed upon the called subscribers line, the signal to is intermittently operated by-being included in serial relation with the normal contacts of the lowermost armature switch of the relayJo, said circuit also including two brushes resting upon a collar w composed of alternating strips of insulating. and conducting material, whereby a characteristic signalis conveyed by thesignal device to. The circuit for said device to may be traced from thegrounded brush bearing upon the collar :12 to the companion brush, the signal device to, the-normal contacts of the-lowermost armature switchof the relay'c, the lowermost armature switch of, relay 7), to the grounded battery {0 The collars u? w are driven by amotor y in circuit with the battery 72 said motor effecting an intermittent inclusion of the generator in circuit and corresponding intermittent operation of the ringing signal w. When the called subscriber responds, circuit through the magnet 11 is closed, thereby excluding the signal w and connecting the normally isolated sections t t of the The relay p having, as has been stated,

' still cord circuit with the answering end of the cord circuit and, consequently, removing the calling generator from circuit. It will be observed that the signal w is individual to its cord and is not common to the signaling generator.- -I have shown but one cord circuit, but it is understood that there are other cord circuits similar in equipment to the cord circuit shown. The energizing circuit for the relay '0 may be traced from the grounded brush bearing upon the collar 2. formed of alternating sections of insulating-and conducting material, the companion brush, when united with the grounded brush by means of a conducting section of said collar, the upper coil of the relay 1;, the unattracted right-hand armature switch of the supervisory relay 3 (the relay s not being adapted to be energized untilafter the relay c has been energized, as will -be apparent by an inspection of the diagram), the called subscribers portion of the tip strand of the cord or plug circuit, the tip line spring of the engaged ack, the limbs of the called subscribers line and the receiver bridge ofthe called subscribers station, the thimble of the jack engaged by the connecting plug, to the grounded battery 77 A locking circuit is established for the relay a when it is energized, which locking circuit may be traced from the grounded terminal of the lower coil of said relay, the attracted lowermost armature switch of said relay,

the attracted lowermost armature switch of relay p, to the grounded battery 10 this locking circuit serving to prevent the re-inclusion of the signaling generator u in circuit with the called line. The locking circuit is broken in order that the normal connection of the isolated sections 25 of the cord circuit may again be established with the generator u,

the opening of said locking circuit occurring whenthe relay p is deenergized, which deenergization occurs upon the break in the circuit of the relay p occurring at the thimble of the engaged jack and the sleeve of the inserted plug when said plug is separated from said jack.

It will be observed that the brushes bearing upon the collar '01 are never in circuit with the brushes bearing upon the collar '5 and that the brushes upon the collar 2 are.

never in circuit with the brushes upon the collar "a in order that current from the ringing generator u may not find passage through the energizing coil ofthe relay. 2.. Crossreferen'ce may be had to my co-pending "application, Serial No. 457,196, filed 1908 and in which some features that are herein disclosed are therein disclosed.

I have thus described the preferred embodiment of my invention, but I do not wish to be limited to the adaptation of the inventelephone lines tails of construction shown, as changes may be made without departing from the spirit of the inventlon.

Having thus described my invention, I

claim as new and desire to secure by Letters Patent 1. A telephone exchange system including telephone lines extending from sub-stations to an exchange, link circuits at the exchange for constituting continuations of calling telephone lines, an operators telephone set, a' relay for including said telephone set in telephonic connection with the calling line, a circuit for said relay governed without the control of the substations and by the answering end of the link circuit, to energize said relay and thereby include the operators telephone set in circuit, and relay mechanism included in a local circuit that contains contacts provided upon the connecting plug and engaged with V a line jack for deenergizing the aforesaid relay, thereby to cut the operators telephone set out of circuit.

2. A telephone exchange system including extending from sub-stations to an exchange, link circuits at the exchange for constituting continuations of calling telephone lines, an operators telephone set, a relay for including said telephone set in telephonic connection with the calling line, a circuit for said relay established without the control of the substations and upon connecting the answering end of the link circuit with a calling line, to energize said relay and thereby include the operators telephone set in circuit, and relay mechanism included in a local circuit that contains contacts provided upon the connecting plug a and engaged with a line.jack for denergm- "ing the'aforesaid relay, thereby to cut the operators telephone set out of circuit.

A telephone exchange system including telephone lines extending from sub-stations to an exchange, link circuits at the exchange for constituting continuations of calling telephone lines, an operators telephone set, a local circuit relay for including said telephone set in telephonic connection with the.

calling line, a circuit for said relay without the control of the sub-stations and governed by the answering end of the link circuit, to energize said relay and thereby include the operators telephone set in circuit, and relay mechanism governed by the connecting end of the link circuit for dei nergizing the aforesaid relay, thereby to cut the operators telephone set out of circuit.

4. A telephoneexchange system including telephone lines extending from sub-stations to an exchange, link circuits at the exchange "for constituting continuations of calling telephone lines, an operatofis telephone set, a local circuit relay for including said teletion herein set forth, nor to the precise dei phone set in telephonic connection with the a 40 I mechanism governed by the connecting end of the link circuit and the jack of a called calling line, a circuit for said relay without the control of the substations and established upon connecting the answering, end of the link circuit with acalling line, to

energize said relay and therebyinclude the operators telephone set in circuit, and relay mechanism governed by the connecting end of the link circuit for deenergizing the aforesaid relay, thereby to cut the telephone set out of circuit. A telephone exchange system including telephone lines extending from sub-stations to an exchange, link circuits at the exchange for constituting continuations of calling telephone lines, an operators telephone set,

a local circuit relay for including saidtelephone set in telephonic connection with the calling line, a circuit for said relay without the control of the sub-stations and governed by the answering end of the link circuit to energize said relay and thereby include the operators telephone set in circuit, and relay mechanism governed by the connecting end of the link circuit and the jack of the calledline, for deenergizing the aforesaid relay, thereby to cut the out of circuit.

6. A telephone exchangesystem including telephone lines extending from sub-stations to an exchange, link circuits at the exchange for constituting continuations of calling telephone lines, anoperators telephone' set, a local circuit relay for including said telephone set in telephonic connection with the calling line, a circuit for said. relay without the control. of the substations and estab lished upon connecting the answering end of the link circuit'with a calling line, to energize said relay and thereby include the operators telephone set in circuit, and relay "line, for deenergizing the aforesaid relay,

thereby to cut the operatorsytelephone set out ofcircuit.

7 A telephone exchange system including telephone lines extending from' substations to an exchange, link circuits at the exchange for constituting continuations of calling telephone lines, an operators'telephone set,

.a local circuit relay for-including said telephone set in telephonic connection with the calling line, a circuit for said relay governed without the control .of the sub-stations and by the answering end of the link circuit, to

energize said relay and thereby include the operators telephone set in circuit, and relay mechanism included in alocal circuit that contains contacts provided upon the connecting plug and engaged with a line jack for deenergizing the aforesaid relay, thereby to cut the operators telephone set out of circuit.

8. A telephone exchange system including telephone lines extending from sub-stations operators operators telephone set to an exchange, link circuits at the exchange for constituting continuations phone set in telephonic connection with the calling'line,a circuit for said relay estabof calling telephone lines, an (iperators telephone set, a local circuit relay for including said tele-- lished without the control of the sub-stations and upon connecting the answering end of the link circuit with a calling line, to energize said relay and thereby include the operators telephone set in circuit, and relay mechanismincluded in alocal circuit that contains contacts provided upon the connecting plug and engaged with a line jack for deenergizing the aforesaid relay, thereby to cut the operators telephone set out of circuit. 4 e p i 9. A telephone switch-board system including telephone lines extending from substations to an exchange,'link circuits for unit nghnes 1n conversatlon, a source ofstations to an exchange, link circuits for signaling current, means for connecting the same with a called line, a local signahng circuit containlng a responsive device ,1nd1- uniting lines in conversation, a source of vidual to the link circuits, supplied in addition to the supervisory or disconnect signals and performingtheir functions independently thereof, said responsive devices being independently operable, and means for impressing upon said circuit -a character istic signaling current during the connection of the source of signaling current with the called telephone line.

'11. A telephone switch-board system including telephone linesextending from substations to an exchange, link circuits for uniting lines in conversation, a source'of signaling current, meansfor connecting the same with a called line a signaling circuit containing a responsive device individual to the link circuits, supplied inaddition to the supervisory or disconnect signals and performing their functions independently thereof, said responsive devices being independently operable, means for impressing upon said circuit a characteristic signaling current during the connection of the source of signaling current with'the called telephone line, and mechanism under the control of the called subscriber for excluding the source of signaling current from; circuit with the called subscribers line; v

12. A telephone switch-board. system ineluding telephone lines extending from substations to an exchange, link circuits for uniting. lines in conversation, .a source of signallng current, means for connecting the same with a called line, a local signaling circuit containing a responsive device individual to the link. circuits, supplied in ad dition to the supervisory or disconnect signals and performing their functions independently thereof, saidresponsive devices being independently operable, means for impressing upon said circuit a characteristic signaling currentduring the connection of the source of signaling current with the called telephone line, and mechanism under the control of the called subscriber for excluding the source of signali current from circuit with thecalled subscrlbers line. I

13. A telephone exchange system including telephone lines extending from sub-stations to an exchange, link circuits at the exchange for constituting continuations of calling telephone. lines, an operators telephone set, arelay for including said telephone set in telephonic connection with the calling line, a circuit for said ,relay without the control of the sub-stations and governed,

by either end of the link circuit, to energize said relay and thereby include the operators telephone set in circuit, and means governed by either end of the link'circu'it companion to the end .of the link circuit that enters into the government of said relay, for eiiecting the deenergization of said electro-' magnetor relay, thereby tocut the opera-v tors telephone set out of circuit.

14: A telephone exchange system including telephone lines extending from sub-stationsto an exchange, cordcircu-its, each provided with terminal plugs adapted'for connection with telephone lines to unite the same in conversation, an operators telephone outfit adapted for telephonic connection with the telephone lines, "switching mechanism I governing the association of, the operators telephone outfit with the telephone lines, an electro-magnet governing the operation of said switching mechanism, a-

source of current for energizing said electro-magnet, switching devices governed by the plugs of each-cord circuit, and circuit connections governed by said plugs and switching devices, whereby when a plug and one of said switching devices co-act, current is caused to flow through said electro-magnet to cause it to operate the switching mechanism, and when both plugs cooperate with both switching devices, current is diverted from said electro magnet to cause it to re lease the switching mechanism that it controls, thereby to remove the operators telephone set from circuitrelation with united telephone lines. p

15. A telephone exchange system'including telephone lines extending from sub-stw t-ions to "an'exchange, cord circuits, each provided with terminal plugs adapted for connection with telephone lines to unite the same'in conversation, said telephone lines having, jack switches for the reception of the plugs, an operators telephone outfit adapted for telephonic connection with the telephone lines, switching mechanism governlng the association of the operators telephone outfit with the telephone lines, an

electro-magnet governing the operation of said switching mechanism, a source ofcurrent for energizing-said electro-magnet, and circuit connections leading to said jack switches and said plugs, whereby when a plug and one of saidjack switches co-ac-t, 'current is'caused to flow through said electromagnet to cause it to operate the switching mechanism, and when both plugs cooperate with both ack switches, current is diverted from said 'electro-magnet to cause it to release the switching mechanism that it con -trols, thereby to remove the operators telephone-set from circuit relation with united telephone lines.

In witness whereof, I'liereunto subscribe my name this 10th day of October A. D. 1998. e

i ELMER R. CORWIN.

Witnesses:

- G. LJCRAGG,

L. G. Srnon, 

